• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.506-508
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• 1998

In this paper, the optimal digital redesign is studied within the framework of fuzzy systems and dual-rate sampling control theory. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the optimal feedback gains developed in the continuous-time system, the constructed fuzzy system is converted into a continuous-time system. The developed continuous-time control law is converted into an equivalent slow-rate digital control law using the proposed digital redesign method. The digital redesign technique using a fuzzy model is employed to simulate the inverted pendulum dynamics.

• 대한전기학회논문지
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• 제32권6호
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• pp.211-218
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• 1983

In this paper, an attempt is made to match the continuous state trajectory of the digital control system with that of its continuous data model. Matching the state trajectories instead of the output responses assures that the performances of the internal variables of the plant as well as the output variables are preserved in the discretization. The mathematical tool used in this research is an extended maximum principle of the Pontryagin type, which enables one to synthesize a staircase type of optimal control signals, such as the output signal of a zero-order hold asociated with a digital controller. A general mathematical expression of the digital controller which may be used to replace the analog controller of a general system while preserving as mauch as possible the performance characteristics of the original continuous-data control system is derived in this paper.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권1호
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• pp.33-40
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• 2000

In this paper, an integrated method for the path planning and motion control of wheeled mobile robots using a hybrid system model and control is presented. The hybrid model including the continuous dynamics and discrete dynamics with the continuous and discrete state vector is derived for a two wheel driven mobile robot. The architecture of the hybrid control system for real time path planning and following is designed which has the 3-layered hierarchical structure : the discrete event system using the digital automata as the higher process, the continuous state system for the wheel velocity controls as the lower process, and the interface system as the interaction process between the continuous system as the low level and the discrete event system as the high level. The reference motion commands for autonomous navigation are generated by the abstracted motion in the discrete event system. The motion control tasks including the feasible path planning and autonomous motion control with various initial conditions are investigated as the applications by the simulation studies.

• 제어로봇시스템학회논문지
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• 제11권9호
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• pp.755-760
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• 2005

This paper proposes an improved implementation algorithm for the continuous-time receding horizon control (RHC). The proposed algorithm has a feature that it has better control performance than the existing algorithm. Main idea of the proposed algorithm is that we can approximate the original RHC problem better by assuming the predicted input trajectory on the prediction horizon has a continuous form, which is constructed from linear interpolation of finite number of vectors. This, in turn, leads to improved control performance. We derive a predictor such that it takes linear interpolation into account and proposes the method by which we can express the cost exactly. Through simulation study fur an inverted pendulum, we illustrate that the proposed algorithm has the better control performance than the existing one.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제30권2호
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• pp.191-201
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• 2023

In this paper the control system described by Urysohn type integral equation is studied. It is assumed that control functions are integrally constrained. The trajectory of the system is defined as multivariable continuous function which satisfies the system's equation everywhere. It is shown that the set of trajectories is Lipschitz continuous with respect to the parameter which characterizes the bound of the control resource. An upper estimation for the diameter of the set of trajectories is obtained. The robustness of the trajectories with respect to the fast consumption of the remaining control resource is discussed. It is proved that every trajectory can be approximated by the trajectory obtained by full consumption of the control resource.

• 한국산업융합학회 논문집
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• 제27권4_2호
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• pp.869-876
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• 2024

In this paper, a tension control system is developed to control temperature deviation due to tension fluctuations in a continuous sterilizer. The fluid flow in the sterilizer is expressed by conservation equations, and the tension control system is modeled using the mass flow rate between two transfer rolls. We analyze the elastic and shear deformation of the internal chain in the sterilizer. As a result of the tension control simulation, it is seen that the tension is recovered about 0.3 sec after the tension deviation. Using a experimental test, we show that the average temperature is similar, but the temperature deviation is improved from 3.1℃ to 1.2℃.

• 한국가스학회지
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• 제9권3호
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• pp.15-20
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• 2005

최근에 환경안전관리는 효과성, 효율성, 우수성이라는 측면에서 사고의 손실비용을 줄이기 위하여 다양하게 접근을 하고 있다. 대부분의 기업은 산업화시대의 대량생산적인 측면에서의 생산성향상보다는 기업을 건전하게 성장시킬 수 있는 손실을 감소시키는데 초점을 맞추고 있다. 본 연구는 석유화학산업에서 기본적으로 운영하고 있는 ISO14001, OHSAS18001, PSM, Responsible Care의 기본적인 요구사항과 지속적 발전을 위하여 요구되는 사항을 분석하여, 손실을 지속적으로 관리할 수 있는 석유화학공장에서의 지속적 발전을 위한 손실관리시스템(LCMCI; the Loss Control Management system for Continuous Improvement of the Petrochemical Industries)를 개발하였다.

• 한국음향학회지
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• 제14권1호
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• pp.81-89
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• 1995

본 논문에서는 연속분포 HMM에 이산 지속시간제어와 회귀계수를 파라메터로 추가한 이산 지속시간제어 연속분포 HMM 모델을 이용하여 한국어 연속음성 인식 시스템을 구성하였다. 또한 25 문장의 로보트 제어명령문을 유한상태 오토마타에 의해 구문제어를 실시한 One Pass DP법으로 인식 실험을 실시하였다. 4연 숫자음에 대한 인식 실험에서 이산 지속시간 제어와 회귀 계수를 포함한 경우 평균 $93.8\%$의 인식율을, 포함하지 않은 경우 $80.7\%$의 인식율을 얻었다. 로보트 제어 명령문의 인식에서는 구문제어를 실시하지 않은 경우 평균 $90.9\%$, 유한 상태 오토마타에 의한 구문제어를 이용한 경우 평균 $98.4\%$로 $7.5\%$의 인식율이 향상되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.45-48
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• 1999

Model predictive control algorithm requires a relevant model of the system to be controlled. Unfortunately, the first principle model describing a polymerization reaction system has a large number of parameters to be estimated. Thus there is a need for the identification and control of a polymerization reactor system by using available input-output data. In this work, the polynomial auto-regressive moving average (ARMA) models are employed as the input-output model and combined into the nonlinear model predictive control algorithm based on the successive linearization method. Simulations are conducted to identify the continuous styrene polymerization reactor system. The input variables are the jacket inlet temperature and the feed flow rate whereas the output variables are the monomer conversion and the weight-average molecular weight. The polynomial ARMA models obtained by the system identification are used to control the monomer conversion and the weight-average molecular weight in a continuous styrene polymerization reactor It is demonstrated that the nonlinear model predictive controller based on the polynomial ARMA model tracks the step changes in the setpoint satisfactorily. In conclusion, the polynomial ARMA model is proven effective in controlling the continuous styrene polymerization reactor.

• International Journal of Internet, Broadcasting and Communication
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• 제4권2호
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• pp.1-6
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• 2012

Control Theory for continuous-time system has been well developed. Due to the development of computer technology, digital control scheme are employed in many areas. When delays are in control systems, it is hard to control the system efficiently. Delays by controller-to-actuator and sensor-to-controller deteriorate control performance and could possibly destabilize the overall system. In this paper, a new approximated discretization method and digital design for control systems with multiple state, input and output delays and a generalized bilinear transformation method with a tunable parameter are also provided, which can re-transform the integer time-delayed discrete-time model to its continuous-time model. Illustrative examples are given to demonstrate the effectiveness of the developed method.